A 3.00-kg mass rests on the ground. It is attached to a string which goes vertically to and over an ideal pulley. A second mass is attached to the other end of the string and released. The 3.00-kg mass rises 50.0 cm in 1.00 s. How large was the other mass?
A) 3.67 kg
B) 4.29 kg
C) 6.83 kg
D) 7.15 kg
E) 7.34 kg

Question

Quizplus · Accepted Answer

The tension in the string is equal to the weight of the 3.00-kg mass, which is 29.4 N. The acceleration of the system is therefore 29.4 N / (3.00 kg + m2) = 9.80 m/s2. The distance traveled by the 3.00-kg mass in 1.00 s is 0.500 m, so the acceleration is 9.80 m/s2. Therefore, the mass of the other mass is 3.67 kg.

A 300-Kg Mass Rests on the Ground